Single handle faucets for the control of both hot and cold water flow have gained wide acceptance in the construction industry as well as with the consuming public. The advantages of such faucets are many and include the capability of mixing or blending hot and cold water from separate sources, selectively allowing flow of only hot or cold water and control the flow volume by manipulation of a single operating handle. A well-known type of single handle faucet valve is the push-pull type that provides for a reciprocal handle movement along the axis of the handle to control water flow volume and rotation of the handle about its own axis to vary the proportions of hot and cold water passing through the valve. Examples of this type of single handle faucet valve are disclosed by U.S. Pat. Nos. 3,170,488, issued Feb. 23, 1965, and 3,204,656, issued Sept. 7, 1965.
Recently, certain parties concerned with plumbing aspects of the construction industry have concluded that it is desirable, and in some cases necessary, that hot and cold water single handle faucet valves be incapable of manipulation so that the operating handle moves from the off position directly to a position whereat water at a high temperature passes through the valve. Additionally, it has been urged that faucet valves of this type be adjustable so that the hot water portion of total flow volume selectively can be limited in response to various hot water temperatures that may be provided by different hot water sources. In fact, in at least one instance, such requirements for single handle faucet valves have been included in governmental building code requirements.
It is, therefore, an object of this invention to provide a single handle faucet valve of the push-pull type such as those disclosed in the above-mentioned patents that is incapable of being manipulated directly from an off condition to a condition wherein only hot water or water at an elevated temperature is supplied through the valve. In particular, the operating handle of the push-pull faucet valve of this invention can be moved from the off position to a hot water only position only by first passing through a relatively high volume cold water only position. Another object of this invention is the provision of a push-pull single handle faucet valve of the type previously described that easily is adjustable to limit the possible percentage of water from the hot water source in the total water flow to compensate the variances in the temperature of hot water supplied from different hot water sources. A still further object of this invention is the provision of a faucet valve having the above-mentioned features provided by structure that is relatively simple in design, reliable in performance and easily may be manufactured, assembled and serviced.